C / C++ / MFC

struct test {<br />
char a;<br />
int b;<br />
};<br />

tuan1111 wrote:

I'm reading bootloader

tuan1111 wrote:

I say the hard things I want them

tuan1111 wrote:

Please provide code

typedef BOOL (WINAPI ALPHABLEND)(HDC, int, int, int, int, HDC, int, int, int, int, BLENDFUNCTION);
typedef ALPHABLEND* LPALPHABLEND;

class ...
{
...
   HINSTANCE m_hLib;
   LPALPHABLEND m_lpfnAlphaBlend;
...
};

// in class c'tor
        m_hLib = LoadLibrary(_T("msimg32.dll"));
        if (m_hLib != NULL)
        {
            m_lpfnAlphaBlend = (LPALPHABLEND)GetProcAddress(m_hLib, "AlphaBlend");
        }

// in class d'tor
    if (m_hLib != NULL)
    {
        FreeLibrary(m_hLib);
        m_hLib = NULL;
    }


BOOL C*********::OnEraseBkgnd(CDC* pDC) 
{
    CDialog::OnEraseBkgnd(pDC);

    if (m_lpfnAlphaBlend != NULL)
    {
        CRect rc;
        GetClientRect(rc);

        BITMAP b;
        if (GetObject(m_hBitmap,
                      sizeof(BITMAP),
                      &b))
        {
            CDC DC;
            DC.CreateCompatibleDC(pDC);
            int s = DC.SaveDC();

            DC.SelectObject(m_hBitmap);
            
            BLENDFUNCTION bf = {0};
            bf.BlendOp = AC_SRC_OVER;
            bf.SourceConstantAlpha = 0x20;

            m_lpfnAlphaBlend(*pDC,
                             (rc.Width() - b.bmWidth) / 2,
                             (rc.Height() - b.bmHeight) / 2,
                             b.bmWidth,
                             b.bmHeight,
                             DC,
                             0,
                             0,
                             b.bmWidth,
                             b.bmHeight,
                             bf);
            DC.RestoreDC(s);
        }
    }
	
    return TRUE;
}

Rozis wrote:

1. Is bf.BlendOp = AC_SRC_OVER; the same as: bf.BlendOp = 0; ??

#define AC_SRC_OVER                 0x00

Rozis wrote:

2. To my opinion you do nothing to add an alpha channel to your bitmap. Thus your bitmap has no alpha channel - do you agree on that?

When the AlphaFormat member is AC_SRC_ALPHA, the source bitmap must be 32 bpp. If it is not, the AlphaBlend function will fail.

Rozis wrote:

3. Because i use another language then you: what does int s = DC.SaveDC() ; do? Is this one essential to Alphablend?

hMemDC:=CreateCompatibleDC(hdc) // ':=' is used as '=' in C
if hMemDC!=NULL_PTR
  hbitmap:=CreatecompatibleBitmap(hdc,w,h)
  hold:=SelectObject(hMemDC,hBitmap)
  Rectangle(hmemDC,0,0,w,h)
  blendfunc.BlendOp:=0       // blendfunc is a structure BlendOp a member of this structure
  blendfunc.BlendFlags:=0
  blendfunc.SourceConstantAlpha:=128 //half transparent
  blendfunc.AlphaFormat:=0
  AlphaBlend(hdc,x,y,w,h,hMemDC,0,0,w,h,@blendfunc) // Here's the troublemaker
//StretchBlt(hdc,x,x,w,h,hMemDC,0,0,w,h,SRCCOPY)
//BitBlt(hdc,x,x,w,h,hMemDC,0,0,SRCCOPY)
  SelectObject(hMemDC,hold)
  DeleteObject(hBitmap)
  DeleteDC(hMemDC)
endif

Rozis wrote:

Think you may ask whats '@blendfunc'. It means 'pointer to structure'.

Rozis wrote:

You're a genius!!!

Rozis wrote:

Saw you're living in Canada, although you have a dutch name.So whenever you are in holland, call me, i have a present for you

kumar sanghvi wrote:

lf.lfHeight= 20;